1. Field of the Invention.
This invention involves arrangements for reliably conducting electrical energy at high levels and, more particularly, electrical circuitry systems which conduct high energy electrical pulses to and from a cartridge case or a similar device which is chambered in a gun.
2. Description of the Related Art.
For cartridge cases and similar devices which are installed and removed rapidly from a gun barrel or mating connection or enclosure, it may be necessary to transfer large pulses of electrical energy. In existing electrically primed cartridges used in automatic cannon, typically small pulses of electrical energy are used to fire the electrical primers. Whether the gun system is self powered or externally powered, an insulated "firing pin" contact located in tile face of the bolt or breechblock contacts or indents into a centrally located primer component which is located in the base or bottom of the cartridge case. This is typically a "one wire system" with the return portion of the circuit being completed by a ground return; i.e., from the outer primer body or outer housing to the cartridge case, from the cartridge case to the barrel and from the barrel to the gun and then to ground. The ground may utilize the gun mount, the carrying vehicle or an electrical conducting wire, bus or similar path.
Where very large energy paths are required and/or a two or more wire system is desired, existing systems offer very limited room for such an expansion. Enlarging existing "routes" may threaten the physical integrity of the bolt or breechblock- In addition, safing interlocks, the requirement that the breechblock functions at up to 1,000 shots a minute or more, and the need for an insulated energy input path to the bolt all create problems.
Systems for electrically igniting the propellant charge in gun-fired ammunition have long been known in the prior art. Typical examples of such systems are found in the following U.S. Pat. Nos.: 1,108,717 of Davis, 3,169,333 of Scanlon, Jr., 3,714,728 of Perkins et al and 3,748,770 of Mitchell. British patent specification 1,102,201 and German Offenlegungsschrift DE 29 49 130 A1 also disclose electrical contact ignition systems for ammunition. The Perkins et al and Mitchell patents and the German Offenlegungsschrift appear to disclose systems using the most conventional approach to electrical ignition: i.e., a single contact centrally located at the rear face of the ammunition round. Such arrangements are clearly subject to the deficiencies and disadvantages noted hereinabove.
The arrangement of Mitchell, while perhaps avoiding some of these problems by utilizing two fixed electrical contacts in the bolt face, is subject to the problems of added complexity of construction and, in systems where the bolt is small or limited in strength or the current flows are very high (as when large conductors are required) , such an arrangement becomes rather impractical as an approach to avoiding the problems of the single conductor igniter.
The British patent relates to initiating systems for propellant charges, clearly directed only to ammunition in large naval guns and the like. It requires charge bags prepared with two strips of tin foil encircling the propellant charge. The barrel includes a threaded hole into which a spark plug is inserted. Not only is a main spark plug required, but there is an auxiliary spark gap to assist in maintaining a spark across the main spark gap. Such arrangements are impractical for systems of the type to which the present invention is directed.
The Davis patent relates to the firing of ammunition in guns mounted on aircraft, probably one of the earliest recoilless rifles. The bore of the gun is open on both ends. Firing the weapon involves blowing the projectile out the muzzle by resort to a compensating mass which is projected rearward through the breech of the gun, balancing the longitudinal strains on the gun and thereby eliminating the shock of recoil. The only way electrical ignition can be accomplished in such an arrangement is by the use of an electrical firing pin mounted in the side of the barrel. The cartridge case has an annular groove into which is mounted a continuous metal band or ring which is insulated from the body of the cartridge case. This is a one wire circuit with the return path being through the metal parts of the gun, mount, etc.